Researchers disprove reported jellyfish increase

An international team of researchers say they have established a pattern in jellyfish blooms that disproves a reported increase in the creatures in recent years.

The Global Jellyfish Group was established several years ago to examine a widespread perception that jellyfish numbers had spiked.

The committee of 30 scientists, including UWA Professor Carlos Duarte, scoured historical records and media reports over centuries and concluded jellyfish numbers increase and drop sharply every 20 years.

Professor Duarte says while it's not clear what causes the cycle, the information will assist northern Australian communities manage the risks posed by deadly stingers.

"It has not been recognised before and in fact no-one had done a global analysis and synthesised all the reliable records to date, so I think it was something that was well overdue to be attempted," he said.

"I think this research will help shape our perceptions around how jellyfish abundance in the sea changes and also help us prepare for the next time a rising phase is due to come up."